With the looming threat of global warming climate change driven by exponentially increasing levels of carbon dioxide in the atmosphere, there is an urgent need to develop new carbon neutral energy production technologies. Even the best of current photovoltaic solar cell technologies in development capture less than half of the available solar energy. Indeed, one of the issues is how to dissipate the “waste” heat in such systems. Thermoelectric modules convert heat to electricity, but demonstrated efficiencies have lagged behind the photovoltaics. If efficiencies could be boosted they would become more attractive for backing up existing photovoltaics as a second power generation stage, or for use standing alone.
Thermoelectric efficiency (called the figure of merit) is proportional to electric conductivity and inversely proportional to thermal conductivity. These two conductivities tend to be related, so the challenge has been to formulate or construct materials where the first is boosted while the second is reduced. Aerogel materials are known for their exceptionally low heat conductivity, and it was hoped that aerogels derived from the best performing thermoelectric bulk materials as a single formula component would offer much better performance, but results by other methods have not yet met those high expectations.